Oh yeah, by the way, that switch...... Did this tech go on to become an elected political official in charge of domestic financial policy? Oh yeah, by the way, the financial regulations that are supposed to prevent these economic meltdowns....

As a freshout designing high voltage circuits for military radar system, some of things I was taught was to work with one hand behind my back, no jewelry (especially if it dangled), don't reach over my circuits. There were many scary stories about carelessness that got people hurt or killed. Never got shocked never had a desire to either. I always remembered to put up my danger high voltage signs and didn't take anything for granted. While I don't design many circuit over 100K anymore I still carry and follow those rules with me today.

Seems you should have followed your own advice prior to learning the hard way! When it comes to anything above 48VAC, I check thrice!. Another lesson: I used to work for a hosiptial fixing these HUGE indistrial washers that used relay logic and stepper switches. No 5Volt logic here - all the ciruits were 120VAC and some were 208VAC. I had to check the panels hot in order to trace down the anomolly. One day my wedding ring got caught on a relay terminal just as it turned on. OUCH. From that day on, I always take off my wedding ring, watch band or anything metallic. Even with 5-Volt logic, you can draw some considerable current from these SMPS, easily frying traces and your finger. Word!

Turn it off, lock it out and then get your voltmeter and make sure it is really off.

Built, installed % service industrial equipment and that is the only way to avoid getting shocked. Generally the shocks don't hurt too bad, but the back of your head does tend to suffer from the reaction...

Gosh, this reminds me of the Inspector Jacques Clouseau sketch from The Pink Panther Strikes Again:

Clouseau: Does your dog bite? Hotel Clerk: No. Clouseau: [bowing down to pet the dog] Nice doggie. [Dog barks and bites Clouseau in the hand] Clouseau: I thought you said your dog did not bite! Hotel Clerk: That is not my dog.

All you home improvement enthusiasts out there should take note. No matter how adept you are are understanding electrical currents, this is still always a danger with home repairs. My husband, who's not an engineer, but a pretty handy guy, has learned this lesson the hard way as I'm sure many of our readers have over the years. Broken switches and nasty shocks are definitely no fun.

Focus on Fundamentals consists of 45-minute on-line classes that cover a host of technologies. You learn without leaving the comfort of your desk. All classes are taught by subject-matter experts and all are archived. So if you can't attend live, attend at your convenience.